Apparatus for drying coated sheet stock



April 17, 1962 H. R. FARWELL APPARATUS FOR DRYING COATED SHEET STOCK 3 Sheets-Sheet 1 Filed Dec. 5, 1958 INVENTOR flarvy .Rusbell ,Faruje ll ATTORNEY April 1962 H. R. FARWELL 3,029,927

APPARATUS FOR DRYING COATED SHEET STOCK Filed Dec. 5, 1958 3 Sheets-Sheet 2 1N VENTOR Bin-5y Rmiyell Fan-well BY ramdd fi ATTORNEY April 17, 1962 R, FARWELL APPARATUS FOR DRYING COATED SHEET STOCK 3 Sheets-Sheet 3 Filed Dec. 5, 1958 IN VENTOR ATTORNEY United rates Patent Ofiice 3,029,927 Patented Apr. 17, 1952 3,029,927 APPARATUS FOR DRYING COATED SHEET STOCK Harry Russell Farwell, Grand Rapids, Mich., assignor to James A. Black, Grand Rapids, Mich. Filed Dec. 5, 1958, Ser. No. 778,337 3 Claims. (Cl. 198-434) The present invention relates to apparatus for drying coated sheet stock, and more particularly to the wicket conveyor type of apparatus for drying printed sheets.

In common practice, wicket conveyors of the endless type are mounted horizontally for movement between a receiving station and a discharge station, the wickets on the upper length of the endless conveyor carrying the printed sheets from the receiving station to the discharge station while the wickets on the lower length of the conveyor are returning empty to the receiving station.

The primary objects of this invention are to provide improved drying apparatus of the wicket conveyor type which is particularly well adapted for drying sheets coated by the screen stencilling process wherein the deposit of coating material is heavy and relatively slow drying; to provide such a wicket conveyor which is so constructed that the coated sheets remain in the wickets throughout practically the entire circuit of the wickets on the conveyor thus virtually doubling the drying time of the sheets, and thus utilizing the maximum capacity of the conveyor and in some cases enabling the use of a shorter conveyor while still accomplishing satisfactory drying of the coated sheets; to provide such a wicket conveyor and novel loading and unloading means therefor which are automatic in operation, thus requiring a minimum of attention; to provide means for immediately and automatically stopping the drying conveyor in case a coated sheet should become jammed in it, thus enabling removal of the jammed sheet so that succeeding sheets cannot become damaged; and in general to provide such a wicket conveyor which is simple and reasonably economical in construction, and eificient and fully automatic in operation.

An illustrative embodiment of the invention is shown in the accompanying drawings, wherein:

FIGURE 1 is a perspective view of the new apparatus for drying coated sheet stock, including the wicket conveyor, and loading and unloading conveyors associated therewith;

FIGURE 2 is a fragmentary, central longitudinal vertical sectional view of the transfer station of the wicket conveyor, seen at the far or left end of FIGURE 1;

FIGURE 3 is a fragmentary, vertical sectional view of the near or receiving end of the drying apparatus, the plane of section being indicated by the line 3--3 of FIG- URE 4; and

FIGURE 4 is a left hand elevational view of the parts of the apparatus seen in FIGURE 3.

Referring now in detail to these drawings, and referring first particularly to FIGURE 1, the sheet drying apparatus there shown is mounted on spaced pairs of uprights 10, 10 and 11, 11. The near uprights 10, 10, as viewed in FIGURE 1, support the receiving end of the apparatus while the far supports 11, 11 support the transfer end. Intermediate supports (not shown) may be provided if necessary. As shown, the uprights extend completely from the floor to the ceiling of the enclosure in which the apparatus is installed. The wicket conveyor, generally designated 12, is mounted on the uprights in an elevated, overhead position so as to leave the floor area beneath it clear for other operations and for passage therebeneath.

The wickets or sheet carriers 13 are mounted on and movable with endless conveyors or sprocket chains 14 which pass around sprocket wheels 15 on a shaft 16 journalled on the uprights 10, and also pass around sprocket wheels 17 on a shaft 18 journalled on the uprights 11. Another sprocket wheel 19 (see FIGURE 4) on the shaft 16 is connected by a chain 20 to operating parts (not shown) of a sheet processing machine 21, which may be a silk screen stencilling machine, and the wicket conveyor is thus driven in synchronization with the sheet processing machine. The upper length of the conveyor travels in an advancing direction from the receiving end or station to the transfer end or station, while the lower length of the conveyor travels in the returning direction from the transfer station to the receiving station.

The wickets or sheet carriers 13 are fabricated of stiff wire, and each comprises a pair of transverse base rods 22, 23 connected at their opposite ends to the blocks 24 secured to links of the conveyor chains 15 and connected to each other by short wires 25, and spaced arms 26 (see FIGURE 4) each comprising a loop of Wire attached at its inner ends to the base rod 22. The sheet carriers 13 project outwardly from the conveyor sprocket chain 14 during their circuitous travel therewith, and are inclined rearwardly-upwardly from the conveyor during their advance trip and rearwardly-downwardly from the conveyor during their return trip.

Inner lugs 27 on the inner ends of the wickets arms '26 are adapted to support stock sheets ltltl during their advance trip, said lugs 27 extending forwardly-upwardly from the arms 26 during the advance trip. Outer lugs 28 on the outer ends of the wickets arms 26 are adapted to support the stock sheets during their return trip, said lugs 23 extending rearwardly-upwardly from the arms 26 during the return trip.

A forwardly-upwardly extending loading conveyor is provided at the receiving end-the near end as seen in FIGURE l of the drying conveyor. This loading conveyor comprises conveyor tapes 30 (see FIGURES l and 3) which pass around pulleys (not shown) on the processing machine 21 and around other pulleys 31 mounted on the upper forward ends of supports 32, the tapes moving in the direction of the arrows. The supports 32 are secured by screws 33 to a cross-bar 34 having its ends secured by screws 35 to the rearward ends of brackets 36 mounted by means of bolts 37 on the uprights 10 at the receiving end of the drying conveyor. The supports 32. extend between the arms 26 of the wickets, so that as each wicket moves upwardly past the conveyor tapes 30 it picks up a stock sheet 109, printed side up. The loading conveyor is driven by mechanism (not shown) inside the processing machine so that it is synchronized with the operations of both the processing machine and the drying conveyor.

An unloading conveyor is mounted for removing the dried sheets 100 from the wicket conveyor at a discharge station near the receiving station, after the sheets have travelled a nearly complete circuit with the drying conveyor. This unloadingconveyor is mounted between side plates 40 which are secured by rivets 41 to the uprights 10 at the receiving station. The unloading conveyor comprises conveyor tapes 42 which pass around lower pulleys 43 on a shaft 44 journalled in the side plates 40, and pass around upper pulleys 45 mounted on the upper ends of supports 46 secured by screws 47 to a cross-bar 48 having its ends secured by screws 49 to the side plates 41). Intermediate pulleys Stl on a shaft 51 journalled in the side plates 40 additionally support the upper rearward, working lengths of the conveyor tapes 42. The shaft 44 has a sprocket wheel 52 (see FIGURE 4) on its outer end, around which passes a sprocket chain 53 for driving shaft 44 and conveyor tapes 42.

The supports 46 for the upper pulleys 45 extend between the arms 26 of the wickets so that as each wicket moves past the supports 24, the stock sheet thereon is picked up by the conveyor tapes 42 and moved quickly" downwardly out of the path of the next succeeding wicket. To this end, the unloading conveyor is inclined sharply downwardly to the rear. Because of this sharp downward. inclination of the unloading conveyor, the sheets 1% would normally have a tendency to leave the conveyortapes 42. To prevent this, weights are provided for pressing the sheets downwardly against the conveyor tapes. These weights are in the form of upper rollers 55 which. bear against the tapes 42 opposite the intermediate pulleys 50, and lower rollers 56 which bear against the tapes 42 opposite the lower pulleys 43. The upper rollers 55 are journalled on arms 57 turnably mounted on a rod 58 secured by screws 59 to the side plates 49, and the lower rollers 56 are journalled on arms 69 also turnably mounted on the rod 58, as shown. Torsion springs 61 urge both sets of arms, 57 and 60, toward the conveyor tapes 42. A collecting box 62 for the completed sheets 100 is mounted by means of screws or rivets 63 on the side plates 40 beneath the unloading conveyor tapes 42.

Operation Stock sheets 100, freshly coated on their upper surfaces or faces by the processing machine 21, are delivered by the conveyor tapes 30 of the loading conveyor to the overhead, Wicket-type drying conveyor, the conveyors being synchronized so that each wicket or sheet-carrier 13 picks up a stock sheet 100 as it passes by the receiving station, as best illustrated in FIGURE 3. The sheets 100 make their advance trip with the drying conveyors upper length from the receiving station at the near and as seen in FIG- URE 1 to the transfer station at the far end as seen in FIGURE 1. During this advance trip the coated sheets 100 are supported by the inner lugs 27 of the wickets, in rearwardly-upwardly inclined positions.

By the time the sheets reach the transfer station seen in FIGURE 2, the coating material on their faces is no longer tacky, but the sheets are still not dry enough to be piled up. As each wicket makes its turn around the sprocket wheels 17 at the transfer station, the sheet 100 thereon falls by gravity to the preceding wicket, and the sheets make their return trip with the lower length of the drying conveyor, resting on the outer lugs 28 (now the lower lugs) of the wickets, in rearwardly-downwardly inclined positions.

When the completely dried sheets 109 reach the discharge station near the receiving station, as seen in FIG- URE 3, the unloading conveyor tapes 42 which extend upwardly between the wire arms 26 of the wickets, pick up each sheet from its wicket and carry the sheet quickly downwardly and out of the path of the next succeeding wicket. The weighted rollers 55 press the sheets 100 down against the tapes 42 during this downward movement, and the sheets are finally piled up in the collecting box 62.

Means are provided for immediately and automatically stopping the apparatus should any sheet become jammed in its wicket, so that the trouble can be corrected, and so as to prevent damage to succeeding printed sheets. Such jamming might occur if for some reason the coated face of one of the sheets should remain slightly tacky by the time it reached the transfer station and thus adhers to the wicket onto which it falls, face down, at the transfer station. When such a sheet reached the discharge station it would, instead of being removed from its wicket by the unloading conveyor tapes 42, depress the upper parts of these tapes so that one of them would strike a microswitch 65 (see FIGURE 3) mounted on one of the supports 46. Suitable electrical connections (not shown) would immediately halt the operation of the drying apparatus and also the operation of the processing machine 21, the loading conveyor and the unloading conveyor.

It will thus be seen that the invention provides an efficient and fully automatic machine for drying coated sheet stock, and while but one specific embodiment of the invention has been herein shown and described, it will be understood that numerous details thereof may be altered or omitted without departing from the spirit of the invention as the same is defined by the following claims.

I claim:

1. Apparatus for drying coated paper sheet stock, comprising: a horizontally disposed endless drying conveyor of the wicket type wherein the coated sheets are carried by carriers each comprising a plurality of horizontally spaced wire arms; electrically driven means for driving said drying conveyor so that its upper length advances from a receiving station to a transfer station while its lower length returns from the transfer station to a discharge station near the receiving station, said carriers depending in a rearwardly and downwardly direction from the conveyor during said returning movement with the sheets supported thereon by means at the outer ends of the carriers; means for unloading the conveyor at the discharge station comprising rearwardly-downwardly extending endless conveyor tapes disposed substantially parallel with the adjacent carrier and having their upper ends extending between the wire arms of the returning carriers whereby the sheets are removed successively from the carriers and moved swiftly rearwardly-downwardly on the conveyor tapes out of the path of the drying conveyor.

2. Apparatus according to claim 1 in which weights are mounted to bear against the unloading conveyor tapes for pressing the stock sheets downwardly against the tapes, said weights comprising rollers turnably mounted on arms pivotally secured to a frame adjacent the conveyor tapes.

3. Apparatus according to claim 1 wherein means is provided for automatically stopping the conveyor if any stock sheet adheres to its carrier to the degree that it depresses the upper parts of said unloading conveyor tapes, said means including a switch arranged to be contacted by a portion of said stock sheet between the conveyor tapes and said switch being adapted to be included in an electrical circuit to said drying conveyor driving means whereby to interrupt said circuit when contacted by said stock sheet.

References Cited in the file of this patent UNITED STATES PATENTS 1,736,866 Wagner et al. Nov. 29, 1929 2,575,744 Burt Nov. 20, 1951 2,706,552 Key Apr. 19, 1955 2,787,363 Howdle Apr. 2, 1957 FOREIGN PATENTS 141,832 Great Britain Apr. 29, 1920 

